Thiele's interpolation formula: Difference between revisions
Added Wren
(Add Swift) |
(Added Wren) |
||
Line 1,497:
pi estimate using cos interpolation: 3.141592653589793
pi estimate using tan interpolation: 3.141592653589794
</pre>
=={{header|Wren}}==
{{trans|C}}
{{libheader|Wren-fmt}}
<lang ecmascript>import "/fmt" for Fmt
var N = 32
var N2 = N * (N - 1) / 2
var STEP = 0.05
var xval = List.filled(N, 0.0)
var tsin = List.filled(N, 0.0)
var tcos = List.filled(N, 0.0)
var ttan = List.filled(N, 0.0)
var rsin = List.filled(N2, 0/0)
var rcos = List.filled(N2, 0/0)
var rtan = List.filled(N2, 0/0)
var rho
rho = Fn.new { |x, y, r, i, n|
if (n < 0) return 0
if (n == 0) return y[i]
var idx = (N - 1 - n) * (N - n) / 2 + i
if (r[idx].isNan) {
r[idx] = (x[i] - x[i + n]) /
(rho.call(x, y, r, i, n - 1) - rho.call(x, y, r, i + 1, n - 1)) +
rho.call(x, y, r, i + 1, n - 2)
}
return r[idx]
}
var thiele
thiele = Fn.new { |x, y, r, xin, n|
if (n > N - 1) return 1
return rho.call(x, y, r, 0, n) - rho.call(x, y, r, 0, n -2) +
(xin - x[n]) / thiele.call(x, y, r, xin, n + 1)
}
for (i in 0...N) {
xval[i] = i * STEP
tsin[i] = xval[i].sin
tcos[i] = xval[i].cos
ttan[i] = tsin[i] / tcos[i]
}
Fmt.print("$16.14f", 6 * thiele.call(tsin, xval, rsin, 0.5, 0))
Fmt.print("$16.14f", 3 * thiele.call(tcos, xval, rcos, 0.5, 0))
Fmt.print("$16.14f", 4 * thiele.call(ttan, xval, rtan, 1.0, 0))</lang>
{{out}}
<pre>
3.14159265358979
3.14159265358979
3.14159265358979
</pre>
| |||